Heat exchanger for cooling liquids



Sept. 30, 1969 H. PHILLIPS HEAT EXCHANGER FOR COOLING LIQUIDS 3 Sheets-Sheet 1 Filed Nov. 20, 1967 ld/fff INVENTOR. EDWA RD H. PH/LL IRS ATTORNEYS I Sept. 30, 1969 E. H. PHILLIPS 3,469,625

HEAT EXCHANGER FOR COOLING LIQUIDS Filed Nov. 20, 1967 3 Sheetslheet f,

I NVENTOR.

EDWARD H. PHILLIPS BYJ ATTORNEYS Sept. 30, 1969 E. H. PHILLIPS 3,469,625

HEAT EXCHANGER FOR COOLING LIQUlDS Filed Nov. 20, 1967 3 Sheets-Sheet S l4b l'2b l3b llb [L1 I ,1 III )1 'Zr1 E t lOb 26 20b I lOb 6 llbfi I u W 5 6 E l3 b INVENTOR. EDWARD H. PHILLIPS ATTORNEYS United States Fatent Cihce 3,469,625 Patented Sept. 30, 1969 3,469,625 HEAT EXCHANGER FOR COOLING LIQUIDS Edward H. Phillips, Los Altos, Califi, assignor to Tydeman Machine Works, Inc., Redwood City, Calif., a corporation of California Filed Nov. 20, 1967, Ser. No. 684,329 Int. Cl. F28f 13/12, 1/12; F04d 29/58 U.S. Cl. 165-125 11 Claims ABSTRACT OF THE DISCLOSURE A heat exchanger comprises a plurality of cooling fins arranged to form intercommunicating chambers and a fan rotatably mounted adjacent to the fins to circulate ambient air therethrough. Passage means are formed at the underside of a plate having the fins mounted thereon to circulate a heated fluid therethrough to transfer the heat through the plate and fins and to the air circulated in the chambers.

Numerous problems have been encountered in attempts to efiiciently cool a heated working fluid utilized for actuating hydraulic motors, for example. Conventional heat exchangers or radiators generally employ an air circulating fan or water-cooled jacket for maintaining the working fluid at a low temperature. Such heat exchangers are oftentimes complex and do not always afford the heat transfer characteristics desired.

An object of this invention is to provide a compact and economical heat exchanger for eflficiently cooling a heated working fluid, such as oil. The heat exchanger of this invention comprises cooling fins mounted in upstanding relationship on a first side of a plate to form at least one air receiving chamber therebetween. A fan means is rotatably mounted adjacent to the cooling fins to circulate ambient air therethrough. Passage means are formed at a second side of the plate to expose the plate to a heated fluid circulated therethrough whereby the heat is transferred through the plate and fins and thus to the air circulated in the chamber formed by the cooling fins.

Further objects of this invention will be understood from the following description and accompanying drawings, wherein:

FIG. 1 is an elevational view, partially sectioned, illustrating the preferred heat exchanger embodiment of this invention;

FIG. 2 is a top sectional view of the heat exchanger taken in the direction of arrows 22 in FIG. 1 with parts removed for clarification purposes;

FIG. 3 is a top sectional view taken in the direction of arrows 3--3 in FIG. 1;

FIG. 4 is an enlarged view of a passage means employed in the heat exchanger;

FIG. 5 is a cross-sectional view illustrating a modification of the heat exchanger; and

FIG. 6 is a top sectional view taken in the direction of arrows 6-6 in FIG. 5 with the fan removed therefrom.

Brief description of the preferred embodiments FIG. 1 illustrates the preferred heat exchanger embodiment of this invention. A plate 10 has at least one cooling fin 11 attached in upstanding relationship on a first side thereof to form at least one air receiving chamber 12 thereby. As clearly illustrated in FIG. 2, a plurality of cooling fins are preferably arranged in spiraled relationship with respect to each other to intercommunicate the chambers for efficient air flow therethrough. A cover plate 13 may be suitably secured to the upper extremities of the fins to close the chambers, if so desired.

A fan means 14 preferably of the squirrel-cage or mixed flow type, is secured to a shaft 15 which rotatably mounts the fan means substantially within the confines of th cooling fins. The shaft is suitably journalled in a housing 16 and is arranged to be driven by an electric motor 17 in a conventional manner to drive the fan to dispel air radially outwardly therefrom. The shaft is further arranged to actuate a hydraulic pump 18 for purposes hereinafter explained. A second plate 19 is suitably attached to the first plate and has circular passage means 20 (FIG. 3) formed therein to circulate a fluid radially inwardly from circular inlet groove 21 to a circular outlet groove 22. Plate 19 could be formed as an integral part of housing 16 if so desired.

Standard gaskets 23 and 24 or O-ring seals may be arranged in a suitable manner to prevent the circulated fluid from escaping thereby. As clearly illustrated in FIG. 3, the circular passage means substantially lies in a plane disposed substantially perpendicularly about a longitudinal axis of the heat exchanger. The passage means preferably comprises a substantially constant depth and constant radial dimension to provide a substantially uniform fluid flow therethrough. Such depth must be sufliciently deep to afford the desired pressure drop and sufficiently shallow to provide adequate heat transfer by conduction and/or convection from the heated fluid to plate 10.

Grooves 21 and 22 should have cross-sectional areas and configurations sufiiciently large to afford negligible pressure drops therethrough. In one application the depth of passage means 20 approximated twenty-thousandths of an inch whereas grooves 21 and 22 were one-quarter of an inch square. Housing 16 and plates 10 and 19 are further arranged to define air passages 25 therethrough to communicate ambient air to fan means 14. Such air flow through the air passages further functions to cool motor 17. A plurality of radially outwardly extending fins are secured at their outer ends to a cylindrical casing of the housing to define such air passages.

As above mentioned, the heated fluid in passage means 20 preferably flows radially inwardly from inlet groove 21 to outlet groove 22. Such flow arrangement functions to yield cross-flow cooling characteristics with respect to the air flow circulating through chambers 12. In particular, cooling characteristics of the heat exchanger are enhanced since the coolest or inboard portions of the cooling fins are arranged adjacent to the outlet means for the circulated fluid. The fluid circulating means comprising a pump 18 (FIG. 1) is preferably arranged to be driven by shaft 15 to pump the fluid within a closed system.

An inlet conduit 28 thereof is suitably arranged to communicate with conduit 26 and inlet groove 21 of the circulating means. A pressure relief valve 27 functions to maintain a predetermined pressure of the working fluid to actuate a hydraulic motor M, for example, via conduit 28 and a three-way control valve 28a, for example.

The fluid exhausted from the motor via valve 28a thereafter communicates with inlet conduit 26 to combine the two fluid flows. Although the intersections of the inlet and outlet conduits with their respective grooves are illustrated as being diametrically opposed with respect to each other, it should be understood that the relative positions thereof may vary. For example, in FIG. 3 the intersection of conduit 29 with groove 22 could be located closely adjacent to conduit 26, i.e., on the left side of shaft 15 rather than on the illustrated right side thereof.

In operation, actuation of motor 17 will function to draw a high volume of ambient air upwardly through radial passages 25 by fan means 14. The air circulates tangentially and substantially radially outwardly through air receiving chambers 12 formed by the cooling fins. Simultaneously therewith, pump 18 will function to pump the fluid to control valve 28a to actuate motor M. The heated working fluid is received at inlet port 21 from the exhaust sides of valves 27 and 28a to communicate such fluid to passage means 20.

Thus, a substantial amount of heat will be conducted through plate 10 and cooling fins 11. In turn, heat will be transferred to the air circulating in chambers 12 to substantially lower the heated fluids temperature. For example, in one two-horsepower system application the fluid was cooled and the average system temperature was held to a maximum of 35 F. above the ambient temperature. The cooled fluid is then returned to the reservoir via outlet means 22 and a return line 29.

It should be noted that inlet groove 21 is preferable arranged at a first radius taken in the direction of a horizontally disposed plane which is substantially greater than a second radius whereat the outlet groove is located. Such an arrangement affords maximum cooling effects on the heated fluid circulated through the passage means, i.e., the passage means provides large surface area contact between the heated fluid and the underside of plate 10. It should be understood that grooves 21 and 22 and passage means 20 could be formed in plate 10.

FIGS. and 6 illustrate a modified heat exchanger embodiment employing the novel constructions and arrangements of this invention therein. Elements common to those above described are depicted by like numerals accompanied by subscripts b. In the FIGS. 5 and 6 embodiment, plate 19 is eliminated and inlet groove 21!), outlet groove 22b and passage means 20b are arranged between superimposed plates 1%.

Inlet passage 26b and outlet passage 2% are diametrically opposed with respect to each other to afford the fluid flow characteristics illustrated in FIG. 6. The grooves and passage means are enlarged somewhat more than normally desired in FIG. 5 for clarification purposes. A central aperture may be formed in upper and lower cover plates 13b to thus permit ambient air to be freely drawn therethrough. Gaskets 23b and 24b may be arranged as shown in FIG. 5 to effect the required fluid sealing thereat. Although grooves 21b and 22b and passage means 20b are shown as formed in both plates 16b, it should be understood that they may be formed in only one plate.

What is claimed is:

1. A heat exchanger comprising at least one spiraled cooling fin mounted in upstanding relationship on a first side of a plate and arranged to form at least one air receiving chamber therebetween, a fan means rotatably mounted adjacent to and substantially within the confines of said cooling fin for circulating air through the chamber formed thereby, closed passage means formed at a second side of said plate and extending substantially across said fins to expose said plate to a heated fluid circulated through said passage means and circulating means for circulating the heated fluid through said passage means whereby heat from said fluid is transferred through said plate and said cooling fin and to the air circulated in the chamber formed by said cooling fin.

2. The invention of claim 1 wherein said passage means is substantially circular and substantially lies in a plane disposed substantially perpendicularly about a longitudinal axis of said heat exchanger, said passage means further comprising a substantially constant cross-sectional area.

3. The invention of claim 1 further comprising a second plate superimposed upon said first-mentioned plate, said passage means formed in said second plate.

4. The invention of claim 2 wherein said circulating means comprises inlet means having a first circular groove arranged to communicate with said passage means at a first radius taken in the direction of said horizontally disposed plane and an outlet means having a second circular groove arranged to communicate with said passage means to a second radius taken in the direction of said horizontally disposed plane which is different than said first radius.

5. The invention of claim 4 wherein said first radius is substantially greater than said second radius.

6. The invention of claim 1 wherein said passage means is formed in said plate.

7. The invention of claim 1 further comprising a housing having said plate mounted thereon and means forming an air passage through said housing and plate to communicate ambient air to said fan means.

8. The invention of claim 1 wherein a plurality of said fins are arranged in spiraled relationship with respect to each other to form a plurality of intercommunicating chambers therebetween.

9. The invention of claim 4 further comprising actuated means operatively connected to said circulating means for receiving actuating fluid therefrom.

It The invention of claim 1 further comprising a second plate arranged in superimposed relationship to said first-mentioned plate, second cooling fins mounted in upstanding relationship on a first side of said second plate and arranged to extend in a direction opposite to said first-mentioned fins to form at least one second air circulating chamber therebetween, said closed passage means arranged between said plates.

11. The invention of claim 10 wherein said fan means is rotatably mounted adjacent to both the first and second cooling fins.

References Cited UNITED STATES PATENTS 1,877,905 9/1932 Le Grand --122 2,368,732 2/1945 Wallgren 165122 2,370,309 2/1945 Hartwig 165-125 X 2,662,748 12/1953 Huber 165-125 X 3,173,479 3/1965 Heuer 165-122 ROBERT A. OLEARY, Primary Examiner THEOPHIL W. STREULE, Assistant Examiner US. Cl. X.R. 230-209 

